1. Field of the Invention
The present invention relates to a grommet for supporting a bundle of electric wires which are inserted, for example, in a fixing hole formed in a partition panel between an engine room and a compartment of an automobile, and particularly to a grommet which comprises an elastic member to be secured around the bundle of the electric wires and a rigid member to be mounted to the fixing hole of the partition panel and being assembled with the elastic member.
2. Description of the Prior Art
When electric wires are wired through a partition panel between an engine room and a compartment of an automobile, it is attempted to protect the wires and seal between the engine room and the compartment by a grommet which is mounted to a fixing hole formed in the partition panel. When such a grommet is integrally formed with rubber, the grommet is excellent in sealability. However, it is difficult to mount the grommet to the partition panel due to its structure. Further, when the wires are pulled with some force, the grommet will likely be removed easily from the fixing hole due to its elasticity.
For these reasons, there is conventionally proposed a grommet which comprises an elastic member formed from rubber to have a sealing effect, and a rigid member formed from a synthetic resin to guarantee attachment to the partition panel. Such a grommet is, for example, shown in Japanese Utility Model Publication No. 59-25115.
The conventional grommet will be described with reference to FIG. 1. Namely, an elastic member 1 has a cylindrical wire securing portion 5 through which a bundle of electric wires 3 passes and in which the bundle is secured, and a sealing lip 9 for contacting a partition panel 7. Further, a rigid member 11 has a flange 15 to be fitted in a groove 13 which is formed inside the elastic member 1, and a lock portion 17 which is in engagement with the partition panel 7 by being flexibly deformed and then restored when the rigid member 11 is fitted to the fixing hole 7a of the partition panel 7.
The grommet having such a construction is mounted to the partition panel 7 by securing the wire securing portion 5 of the elastic member 1 around the bundle of the electric wires 3, inserting the flange 15 of the rigid member 11 into the groove 13 of the elastic member 1, and then assembling integrally the elastic member 1 and the rigid member 11. Thereafter, thus integrally assembled grommet is inserted and fixed to the fixing hole 7a of the partition panel 7 from the left side of the partition panel 7 in the drawing.
However, in the conventional grommet, the flange portion 15 of the rigid member 11 needs to be fitted into the groove 13 formed inside the elastic member 1 when the elastic member 1 is assembled with the rigid member 11, and so the groove 13 must be expanded outwardly at that time in order to receive the flange portion 15 in the groove 13. Moreover, the bundle of the electric wires 3 becomes a hindrance during the fitting operation because it is present inside the grommet.
In order to eliminate the trouble caused by the bundle of electric wires 3, it is possible to assemble the elastic member 1 and the rigid member 11 integrally before the bundle of electric wires 3 is inserted into the elastic member 1. However, since the wire securing portion 5 of the elastic member 1 has to be generally expanded at the time of the insertion of the bundle of the wires 3, the elastic member 1 may come off the rigid member 11 due to the expansion, so that this method is not preferable. In addition to this, since the flange 15 of the rigid member 11 is urged from the outside thereof by the elastic member 1, these two members are likely to be disengaged.